1. Field of the Invention
The invention relates to pixel elements and, particularly, to a pixel element for a field emission display.
2. Discussion of Related Art
Field emission displays (FEDs) are based on emission of electrons in vacuum. Electrons are emitted from micron-sized tips in a strong electric field, and the electrons are accelerated and bombard a fluorescent material, and then the fluorescent material emits visible light. FEDs are thin, light weight, and provide high levels of brightness.
Carbon nanotubes (CNTs) produced by means of arc discharge between graphite rods were first discovered and reported in an article by Sumio Iijima, entitled “Helical Microtubules of Graphitic Carbon” (Nature, Vol. 35, Nov. 7, 1991, pp. 56-58). CNTs also feature extremely high electrical conductivity, very small diameters (much less than 100 nanometers), large aspect ratios (i.e. length/diameter ratios) (greater than 1000), and a tip-surface area near the theoretical limit (the smaller the tip-surface area, the more concentrated the electric field, and the greater the field enhancement factor). These features tend to make CNTs ideal candidates for electron emitter in FED. However, single CNT is so tiny in size and then the controllability of the method manufacturing is less than desired. Further, the luminous efficiency of the FED is low due to the shield effect caused by the adjacent CNTs.
What is needed, therefore, is a pixel element for FED, which has high luminous efficiency and can be easily manufactured.